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Java example source code file (Basic.java)

This example Java source code file (Basic.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

basicfileattributes, basicfileattributeview, file, ioexception, outputstream, path, posixfileattributes, runtimeexception, string, threading, threads, unsupportedoperationexception, utf\-8, util

The Basic.java Java example source code

/*
 * Copyright (c) 2008, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/* @test
 * @bug 4313887 6838333
 * @summary Unit test for java.nio.file.attribute.BasicFileAttributeView
 * @library ../..
 */

import java.nio.file.*;
import java.nio.file.attribute.*;
import java.util.*;
import java.util.concurrent.TimeUnit;
import java.io.*;

public class Basic {

    static void check(boolean okay, String msg) {
        if (!okay)
            throw new RuntimeException(msg);
    }

    static void checkAttributesOfDirectory(Path dir)
        throws IOException
    {
        BasicFileAttributes attrs = Files.readAttributes(dir, BasicFileAttributes.class);
        check(attrs.isDirectory(), "is a directory");
        check(!attrs.isRegularFile(), "is not a regular file");
        check(!attrs.isSymbolicLink(), "is not a link");
        check(!attrs.isOther(), "is not other");

        // last-modified-time should match java.io.File in seconds
        File f = new File(dir.toString());
        check(f.lastModified()/1000 == attrs.lastModifiedTime().to(TimeUnit.SECONDS),
              "last-modified time should be the same");
    }

    static void checkAttributesOfFile(Path dir, Path file)
        throws IOException
    {
        BasicFileAttributes attrs = Files.readAttributes(file, BasicFileAttributes.class);
        check(attrs.isRegularFile(), "is a regular file");
        check(!attrs.isDirectory(), "is not a directory");
        check(!attrs.isSymbolicLink(), "is not a link");
        check(!attrs.isOther(), "is not other");

        // size and last-modified-time should match java.io.File in seconds
        File f = new File(file.toString());
        check(f.length() == attrs.size(), "size should be the same");
        check(f.lastModified()/1000 == attrs.lastModifiedTime().to(TimeUnit.SECONDS),
              "last-modified time should be the same");

        // copy last-modified time from directory to file,
        // re-read attribtues, and check they match
        BasicFileAttributeView view =
            Files.getFileAttributeView(file, BasicFileAttributeView.class);
        BasicFileAttributes dirAttrs = Files.readAttributes(dir, BasicFileAttributes.class);
        view.setTimes(dirAttrs.lastModifiedTime(), null, null);

        attrs = view.readAttributes();
        check(attrs.lastModifiedTime().equals(dirAttrs.lastModifiedTime()),
            "last-modified time should be equal");

        // security tests
        check (!(attrs instanceof PosixFileAttributes),
            "should not be able to cast to PosixFileAttributes");
    }

    static void checkAttributesOfLink(Path link)
        throws IOException
    {
        BasicFileAttributes attrs =
            Files.readAttributes(link, BasicFileAttributes.class, LinkOption.NOFOLLOW_LINKS);
        check(attrs.isSymbolicLink(), "is a link");
        check(!attrs.isDirectory(), "is a directory");
        check(!attrs.isRegularFile(), "is not a regular file");
        check(!attrs.isOther(), "is not other");
    }

    static void attributeReadWriteTests(Path dir)
        throws IOException
    {
        // create file
        Path file = dir.resolve("foo");
        try (OutputStream out = Files.newOutputStream(file)) {
            out.write("this is not an empty file".getBytes("UTF-8"));
        }

        // check attributes of directory and file
        checkAttributesOfDirectory(dir);
        checkAttributesOfFile(dir, file);

        // symbolic links may be supported
        Path link = dir.resolve("link");
        try {
            Files.createSymbolicLink(link, file);
        } catch (UnsupportedOperationException x) {
            return;
        } catch (IOException x) {
            return;
        }
        checkAttributesOfLink(link);
    }

    public static void main(String[] args) throws IOException {
        // create temporary directory to run tests
        Path dir = TestUtil.createTemporaryDirectory();
        try {
            attributeReadWriteTests(dir);
        } finally {
            TestUtil.removeAll(dir);
        }
    }
}

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